i had the same problem with my quad door, what i had to do was take the panel off, its a real hassle since it doesnt open, but once you get it off take out the speaker so you can fit your hand back there, i think there is more than that hole back there but that was the easiest one for me, and just feel around of a thin bar if you find that and you can move it around not good thats why it wont open, just feel around for a little latch thing that has a hole that should have something there but there isnt, thats where the bar goes, thats what was wrong with mine yours might be different but idk hope i helped

 

Idk what it is with Chrysler latching mechanisms but they have a tendency to lock up. Mine had that problem as well as a Jeep Liberty that I worked on with my dad. At least the liberty had a separate panel that could be removed just for accessing the latch on the back hatch.

 

They would only be round if someone before you installed new ones.
I am going to assume that you are new to car audio, and while I'm trying to make fun of you, there are some points that you are missing. Judging from your first post about the speakers, I can fairly say you don't know much.
Firstly, the equalizer comment about assuming that there is only three speakers, to accommodate the three different equalizer settings is wrong. Just sayin. You will have four speakers from the factory. What other owners did is, well frankly, just what they did.
Those three settings have no impact on how many speakers you have.
Sound is measured in hertz/megahertz. Those three settings merely allow you to adjust the high-Treble, Mid, and low- bass, frequencies. Most aftermarket decks will allow you to go in a set each frequency range individually, instead of just grouping them into three generic settings.

As I said before, here is the FACTORY specifications on speaker size:
Front: 6x9 (oblong)
Rear doors/Wall speakers: 5 1/4: (Round)

Here is what can commonly be used in place of those that I listed above:
Front: 6 1/2" Round speakers.
Rear: 6 1/2" round speakers.

It's common practice for those that like extra bass, but don't want the hassle of installing woofers.

Now, since I think your hinting at doing a full speaker replace, I will go ahead and share some tips. If you go and buy all new speakers, you should really thing hard about converting the fronts to round size. IMO, it's not worth the hassle involved to do one right, and 90% of the people that do it, fail to do a clean install. If you want decent mid range speakers, I suggest looking at brands like Pioneer, Kenwood, fosgate, clarion, and those of the like. If you want to start getting into component speakers, then I would push you into brands like Infinity, Alpine, Eclipse, and those of the same like.
One thing you must not forget. ALWAYS ALWAYS REPLACE THE STOCK WIRES. This is more important to you since you have the infinity system that has the worthless amps, and their hair pulling wire mess that comes free of charge.

I am an audio nut, so feel free to ask more questions.

 

You should do a DIY on rewiring to remove the Infinity system. You would get sooooooo many hits on that thread.

If he had the fancier system he might have 6 speakers counting tweeters lol.

 

I appreciate the comment, but I have never created that thread for a few reasons.
1. My truck didn't have the Infinity Speakers, even though it is a Laramie. Came with Audio Latinas
2. Although I have done stereo installs on many of the 2nd gen Dodge trucks, and while all of them had the Infinity system, we by passed all of it. See, the people that I hang out with, and the same ones that got me involved in audio, don't skimp out on their builds. I was taught with the same principles. We NEVER reused the factory wiring harness. Failure to run all new wiring in a system can severely cripple your build's sound quality. I have seen far too many people drop thousands of dollars on a system, and they don't change the wiring, then they call me and complain about how my advice was ****ty. I can't make a lot of people understand that wire is about the second most important thing in car audio. The first would be the actually speaker install.

 

I fix my driver quad door today (THANK GOD). Here it is use a big flat screw driver to wedge in between the latch plate and latch it self to relive pressure of hindges on door. this wil require two people one get ins side truck with a foot to foot and a half 2x4 and a 5# sledge hammer. person 2 pull latch handle so it is released. meanwhile #1 put a 2x4 bottom edge of door and swing away. mine poped open on the 3rd swing. however latch arm wil break. so make sure you have new one. Have fun!!!!!

 

your latch mechanism in the door at the bottom is all siezed up.

hold the handle in the open ad pull hard it should pop loose then lube and work door everything will free up.

keep doors well lubed.